(noun) - Xylography is wood engraving, and the oldest known relief printmaking technique. The discipline was first practiced in China, then picked up in Europe centuries later. Using a block of wood in somewhat the same manner as a rubber stamp, a xylographer cuts and/or carves wood away from those parts of the design that will not be inked. The "sticking up" parts that are left form the final print.
(P.S. This is a devilishly tricky process, if one has difficulty visualizing things backwards, or mentally switching positive for negative. Or if one has difficulty reading the grain of wood. Or with sharp objects in general. Kudos to that eye-hand genius Dürer, both for his Apocalypse series and for leaving this earth with all ten fingers intact.)
Xylography also means "not typography", when used to print texts (mind-boggling, *that* prospect) or illustrations from woodblocks. If a color other than black is part of the final print, separate, coordinating blocks must be painstakingly carved for each color. (And we wonder why xylography isn't a thriving art ... )